The broad objective of this interdisciplinary project is to elucidate the pathogenesis of human neuromuscular diseases. The Center comprises six laboratories; Muscle Disease Biochemistry; Cytology and Cytopathology; Clinical Neurophysiology; Cell Biology and Muscle Tissue Culture; Neurophysiology; and Neurochemistry. Investigators in these laboratories will conduct individual projects and will collaborate in joint enterprises including: evaluation of sarcolemmal abnormalities as the proximate cause of muscular dystrophies; abnormal mitochondrial function and lack of carnitine-palmityl transferase as cause of other myopathies; possible role of antibodies to acetylcholine receptor substance and other muscle proteins in myasthenia gravis; physiological studies of surface membrane, excitation-contraction coupling and contractile apparatus in muscular dystrophies; possible viral causation of polymyositis; use of muscle cell cultures to evaluate factors responsible for cell fusion, especially acetylcholinesterase and polyamines, to evaluate a possible defect of adenyl cyclase in dystrophic muscle, and to evaluate possible neurogenic influences in myopathies; physiological studies of neonatal neuromuscular function to evaluate potential drug hazards and other aspects of maturation in the newborn period, and of disorders of neuromuscular transmission in adults; and to evaluate the fundamental biochemical properties of acetylcholine receptor in electric organ and mammalian muscle and of acetylcholinesterase. A Muscle Clinic will serve to bring the potential benefits of investigations to patients promptly.